real_polygamma

Description

Derivative of the psi function (x)

Syntax

double real_polygamma( double x, int k )

Parameters

x

[input] the argument x of the funtion

k

[input] the kth derivative to be evaluated

Return

Returns the value of the kth derivative of the psi functions (x) for real x and k=0,1...,6

Examples

EX1

void real_polygamma_ex1()
{
        int k =2;
        double x =0.7;
        printf("%2ld   %4.1f:  %12.4e\n",k,x,real_polygamma(x,k));
}

Remark

See Also

header to Include

origin.h

Reference